This invention relates to convertible sofa beds suitable for sitting and for sleeping.
A convertible sofa bed should be simple, inexpensive, easy to operate and stable when in the retracted and extended positions. When in the sofa configuration, the unit should be attractive with pleasing proportions and sloped back and seat for sitting. When in the bed configuration, the bed should be horizontal and supported at the corners or edges to avoid rocking and tilting.
A variety of designs have been proposed in the past, including those shown in U.S. Pat. Nos. 1,140,368; 2,573,892; 2,907,053; 2,937,384; 3,005,997; 3,167,788; and 3,299,446. These prior art units have various disadvantages. Some require complex mechanical linkages to achieve the movement between the sofa and bed configurations. One prior art unit utilizes a simpler mechanical linkage with an overhanging or cantilevered seat for the bed configuration with a resultant lack of stability. The stability is improved in some prior art units by utilizing additional legs at the front edge of the moving seat, however the legs are exposed at the forward edge of the sofa when in the sitting configuration resulting in an unattractive design.
It is an object of the present invention to provide a new and improved convertible sofa bed incorporating a simple mechanical mechanism and one which is easily moved between the sitting and sleeping configuration. A further object is to provide such a convertible sofa bed where the moving seat rests on the sofa frame when in the retracted or sitting configuration with the seat support legs behind the forward edge of the sofa frame, and with the seat supported at opposite sides or at the four corners when in the extended or sleeping configuration.